In the medical field, doctors and scientists are striving to find less invasive ways to treat patients. By using treatments that are less intrusive to the body, doctors can greatly reduce the stress on the patient's system and exposure to infection. For example, laparoscopic techniques enable physicians to explore the interior of the body and perform surgery through a small opening in the skin. Less intrusive medical techniques are extremely beneficial when applied to cardiovascular diseases, for example.
Cardiovascular diseases affect millions of people, frequently causing heart attacks and death. One common aspect of many cardiovascular diseases is stenosis, or the thickening of the artery or vein, which decreases blood flow through the vessels. Angioplasty procedures have been developed to reopen clogged arteries without resorting to a bypass operation. However, in a large percentage of cases, arteries become occluded again after an angioplasty procedure. This recurrent decrease of the inner diameter of the vessel is termed restenosis. Restenosis frequently requires a second angioplasty and eventual bypass surgery. Bypass surgery is very stressful on a patient, requiring the chest to be opened, and presents risks from infection, anesthesia, and heart failure. Effective methods of preventing or treating restenosis could benefit millions of people.
One treatment for restenosis that has been attempted is radiation of the vessel wall. For example, U.S. patent application Ser. No. 08/701,764, filed Aug. 22, 1996, titled "X-ray Catheter," describes an X-ray device for insertion into a lumen of a body, capable of localized X-ray radiation. U.S. application Ser. No. 08/701,764 is hereby incorporated by reference in its entirety. There are many difficult technical issues associated with delivering localized X-ray radiation to the interior of a patient's lumen. U.S. Pat. No. 5,854,822, titled "Miniature X-ray Device Having Cold Cathode" discusses improved cathode configurations that improve the rate of electron emission and decrease the required electric field. U.S. Pat. No. 5,854,822 is incorporated herein by reference in its entirety.
There is a need for effective devices to be used to treat the interior of the body with minimal intrusion. Effective, less invasive techniques for preventing and treating stenosis and restenosis at a lumen wall are especially needed. Size improvements on an X-ray device reduce the size of the required incision, improve maneuverability, decrease the stress on the lumen, and enable the device to reach more remote locations in the patient's body. Other applications for localized X-ray radiation are numerous, such as treating the interior of the esophagus, and providing radiation to tumors. Further, numerous non-medical applications require miniature x-ray devices that operate effectively, simplify manufacturing, and minimize the required voltage. For example, investigation of very small spaces can be performed using localized x-ray radiation.